I main trist. She is my spirit animal. I'm not that great at the game but when I'm her 99% of the time I feel like a god. I win most of my games as her and even the ones I lose I almost always win my lane. But everyone a talk to says trist ain't got shit on 
or
lately. Trist is getting a lot of attention in worlds but I got to know. Is she still the best?
I main trist. She is my spirit animal. I'm not that great at the game but when I'm her 99% of the time I feel like a god. I win most of my games as her and even the ones I lose I almost always win my lane. But everyone a talk to says trist ain't got shit on
It really depends on what you're trying to accomplish in the game, tbh. If you're good with trist, stick with her. She's great for siege comps, solo pushing and I guess still somewhat of a hyper carry due to her steroid and range? Really you should just play whoever you're comfortable with.+
Best is relative but I feel like she is, until she gets a real rework she has the most broken kit of them all. Safe and strong while still being a hyper carry. Best is also situational, but I feel like she has a kit that lets her be good in any meta and always a broken champ late game.
Massive Range Steroid Escape / Gap closer Burst / Aoe Burst / Peel
The good adcs are 
in no particular order.
She and Jinx are pretty close.
Kog is the best IMHO. He has insane range and % health damage to take down anyone.
